Piston packing



May 6 E924, EAQZEYB c. L'. CASE PISTOQN PACKING Filed March 5, 1921 & 44 yaw;

Patented Ma a, ieae.

ear

CHARLES L. CASE, OF WINCHESTER, MASSACHUSETTS, ASSIGNOR TO PRESSUREPB/OOF PISTON RING- COMPA1 \l'Y,O'F BOSTON, MASSACHUSETTS, A.CORPORATION OF MASSA- CHUSETTS.

PISTON PACKING.

Application filedmaroh 5, 1921. Serial Ito. 4%,729.

To all whom it may concern: Be it known that 1, CHARLES L. CAsE, acitizen of the United States of America, and resident of Winchester, inthe count of Middlesex and State of Massachusetts, ave invented, new anduseful Improvements .in Piston Packings, of which the following is aspecification. This invention relates to piston packings and moreparticularly to that type of packing which is especiall designed toprevent a preciable escape 0 gas between it and t e end wall of itsgroove.

The object of the present invention is-to 15. provide a packing ofsimple and improved form which shall at all times fit snugly aainstrboth side walls of the piston groove w erebynot only to obstructthe leakage of gas but also to restrain such ring against anyappreciable axial reciprocation mits groove.

referred arrangement of arts for carrymg this object into 'efiect is iustrated in the accompanying drawings in which-.-

Fig. 1 is a fragmentary diametral cross section of an engine cylindershowing a piston therein provided with. a packing of the type formingthe subject of this application.

Fig. 2 is a fragmentary cross section to enlarged scale through thepiston and cylinder wall showing the packing'in position.

Fig. 3 is a view similar to Figl 2 but illustrative of a modified formof ring.

Fig. 4 is a development of the packing ring of'Fi 2 looking from theright-hand side of sai figure. n.

Fig. 5 is a view similar to Fig. 4 but illustrating a modification; andi Figs. 6*and 7 are fragmentary views similar to Fig. 4 but showingfurther modifications. c

The wall of an engine cylinder of ordinary construction is illustratedat 1. The piston 2 may be providedwith one or morecircumferentiaLgrooves .3 of usual construction for the reception of thepiston packing devices. The piston packing herein disclosed comprises apair of coinplemental rings 4, 5, such rings being split as indicated at6, 7, to provide for their radial expansion in the usual manner. Theradial, mutually engaging surfaces of said rings are prefer- ,ablydivided into two portions 8, 9, having interposed therebetweenperipheral engaging surfaces as indicated at 10. Withthis arrangementslight axial movement of the rings is. permitted While maintaining atight joint therebetween.

The side walls of the.

piston groove indicated at 11, 12, respectively, engage the surfaces 13,14 of. the rings 4, 5. i

The rings 4, 5, are provided with complemental recesses 15, 16, whichtogether form a spring receiving "chamber. such recesses will be ofannular form, thus providing an annular chamber or channel open at theinner face of the combined ack in'gydevice. The oppositely facing wal s19,

20, of said chamber may be provided with 7 pockets or recesses 17, 17,18, 18, respectively. With such pockets may be engaged the bends 23 andt e ends 24 of zigza or W-shaped springs 21, the bends thereo engagingthe pockets 17, 18 and the ends engaging 'the pockets 17 18", of therespective rings. Such zigzag springs are preferably formed of flatribbon like material suitably bent and tempered. These springs, whiletending to urge the rings 4,5, in opposite by the packing rings andhavin no engagement with any other part, are ee to'move Preferablyoutwardly with such rings when the latter expand.

While the slip joint arrangement indicated in Fig. 2 between'the rings 4and 5 is preferred, a butt joint such as indicated at 8", 9 between'therings 4, 5 of Fig. 3 may be employed.

By'the seating of the springs 21 in pockets in the opposite facesof therings 4, 5, it is clear that any tendency of the latter to rotaterelatively one to the other is prevented, while by reason of theconstant pres sure of each spring in an axial direction anyreciprocation of the packing within the groove 3 is avoided. The packingis thus at all times maintained in such operative relation to the pistongroove as to prevent leakage of gas theret rou h, while at the same timeany tendency o the packing to rock in its oove or to move longitudinallytherein wit attendant wear upon the groove and cylinder Walls isavoided.

It is to be understood of course, that while in a preferred arrangementeach spring 21 will be of substantially W-shape, a series of suchsprings being provided extending along the annular chamber between 1springs illustrated in the preceding figures,

a helical coil spring 41 is employed, such spring being seated at itsopposite ends in pockets 47, 48, in the respective rings. In

ig. 7 a still further modification is illustrated, in which a helicalspring 51 is positioned by means of a post 57 secured in one of therings and engaging a pocket 58 in the other ring. Whlle but a singlespring has been shown in each of the last described cases, it is evidentthat a series of such springs will be em loyed properly spaced about thepacking evice.

It is furthermore clear that while the device shown in Figs. 2 and 4 isa preferred form, the spring arrangements shown in the other figuresserve in a'similar manner. both to urge the rings in opposite directionsand also to restrain the rings against rotation.

Having thus described the invention in a preferred embodiment of thesame together with the mode of operation thereof, what I claim anddesire to secure by Letters Patent of the United States is:

1. A packing for use with a unitary metallic piston having acircumferential groove, comprising a pair of complemental radiallyexpansible split rings provided respectively with grooved engagingradial. faces and having peripherally overlapping portions andcomplemental recesses in their inner faces collectively constituting acon tinuous circumferential groove, and a plurality of independentcircumferentially spaced springs within said groove positioned wholly byengagement with the respective rings and constructed and ar ranged toexert force in an axial direction only for urging the respective ringsinto contact with the side walls of the piston groove, one at least ofthe split rings having means engaging the springs for preventingrelative circumferential movement of the latter.

2. A packing for use in the groove of a unitary metallic pistoncomprising a pair of independent radially resilient split ring membershaving peripherally engaging surfaces, and a plurality of independentsprings interposed between opposed faces of said rings, each springhaving its ends disposed to engage one of the rings and an intermediatepart arranged to bear directly against the other ring, said springscollectively exerting a force in an axial direction only normallytending to move said rings in opposite directions axially of the piston.

3. A packing for use with a unitary piston having a circumferentialgroove, comprising a pair of expansible split rings provided withperipherally overlap ing portions and having complementa recessesforming a spring receiving chamber, and a series of circumferentiallyspaced independent springs within said chamber, each spring havingportions bearing against the respective rings whereby to ur e them inopposite directions, the rings ein furnished with elements cooperatingwith the bearing portions of the several springs to preventcircumferential movement thereof relatively to the rings.

4. A packing device comprising a air of radially resilient rings havingcomp emental recesses therein forming a spring receiving chamber, springosltioning means,

and a series of indepen ent springs of W shape engaging said positioningmeans and bearing against elements of the respective rings, alternatesprings of the series being inverted relatively to the others.

5. A packing of the class described comprising a pair of rin s havingcomplemental annular recesses therein forming an annular chamber, aseries of sprin positioning pockets formed in the wa s of said chamber,and a plurality of peripherally disposed springs engaging said pockets.

6. A packing device comprising a pair of complemental expansible ringshaving a chamber therebetween, and a series of independent flat springsof W form within said chamber and engaging pockets in opposed faces ofthe respective rings whereby simultaneously to urge said ringsoppositely in an axial direction and to prevent axial ro-I.

tation of said rings.

7. In combination with a unitary pistonhaving a peripheral groovetherein, a packing seated within said groove and comprising complementalexpansible split rings provided with peripherally engaging surface, saidrings being of an internal diameter greater than that of said groove andhaving an annular chamber therebetween open at the inner face of saidrings, a series of independent fiatsprings of sinuous form within saidchamber reacting agalnst said .rings to urge them oppositely intocontact with the side walls of said groove, said springs being free fromengagement with the bottom Wall of said groove and being constructed andarranged to react a ainst said rings in substantially an axia directiononly, and spring positioning means carried by the respective rings.

8. In combination with a unitary piston having a circumferential. groovetherein, a

pair of radially expansible split rings in said groove, said ringshaving peripheral engaging surfaces, and a series of independentcircumferentiallyspaced springs free of engagement with said piston, forurging said rings oppositely into engagement With opposite walls of thegroove, said springs having portions thereof seated in positioningrecesses in the rings.

Signed by me at Boston, Massachusetts, this first day of March, 1921.

. CHARLES L. CASE.

